Some embodiments relate to a vehicle electronic controller provided with a microcomputer, and a port expansion element that provides a plurality of signal inputs in response to an instruction that is transmitted from the microcomputer.
Some related art vehicles, such as automobiles, are provided with electronic controllers that perform various controls, such as traveling system control, power system control, onboard network system control, etc. These electronic controllers are generally referred to as ECU's (Electric Control Units).
In a vehicle's ECU, a microcomputer outputs a control signal of an onboard device through an input/output port, based on a signal showing a state of the vehicle that is input through the input/output port.
For example, Japanese Published Patent Application 2002-127848 discloses an ECU provided with a port expansion element that performs a plurality of signal outputs in response to an instruction from a microcomputer. In this case, a microcomputer can input or output a plurality of signals through one communication port.
By using a port expansion element, the number of input/output signals needed for control processing can be easily changed without changing a main structure of an ECU that utilizes a microcomputer for executing control programs.
In accordance with a related art ECU for a vehicle with a port expansion element, a microcomputer communicates with the port expansion element in a predetermined cycle, a signal showing a vehicle state is input, and a control signal is output.